$f\left(x\right)=\frac{cos\left(x\right)-cos\left(6x\right)}{x^2}$

$3\ln\left(5x\right)=0$

$12=v+2$

$\left\{\left(31+\left(-8\right)\right)-\left[\left(-17\right)-16+\left(-14\right)\right]\right\}-41$

$\frac{dy}{dx}=3x^2+5x$

$\left(\left(e^x\right)\left(e^{2x}\right)\right)+\left(\left(e^x\left(e^{2x}\right)\right)\right)$

$1385-\left(807\right)+99$